A 600mm f/5.6 prime has to have good IQ. It doesn't necessarily need to be as good as the 600/4, but it has to be better than the alternatives. For such a large objective element, that is no easy task...

We are definitely in agreement...

For a 600 F5.6 prime to sell, it has to be better than the alternatives.....

At twice the price, it has to be significantly better than the Tamron... But I doubt they can hit that combination of quality and price... As mentioned above, nobody thought they could hit the quality/price on the 150-600 and they proved us wrong...I am more than willing to be proved wrong again, but I'll believe it when I see it.

Shot this with the Tamron today at 600mm. Pixel peeping on an obsolete crop body To significantly beat this at a reasonable price will certainly be a challenge.

I can't imagine a person who just spent $12,000 on a 600mm lens having anything good to say about a new 600mm lens that costs $1,200. You can be sure that each lens has advantages and disadvantages. If somebody would give me one lens or the other I would choose and suffer with the disadvantages of the $12,000 lens.

It has nothing to do with the fact that I bought a 600mm f/4 lens. It's a logical deduction. If you are going to buy a 600mm f/5.6 prime, the general expectation is that it fits the general description of a prime. You don't expect any prime lens to offer lower quality than a similar focal length from any zoom lens. Most people would natrually compare it to the best of the relevant zoom range, in which case the Canon 100-400 L, which has very little CA at 400mm, is the likely target. Any 600mm f/5.6 prime would have to be better than the 100-400 L @ 400mm.

And, as a matter of fact, I do have good things to say about Tamron's lens. For it's price point, it's a game changer. It offers excellent features and great quality relative to it's competition for an eminently affordable price. It's because I have good things to say about Tamron's lens that I do not believe a 600mm f/5.6 prime lens is viable.

There really isn't a middle ground option to be had. Building a good quality 600mm f/5.6 lens, especially if you cut some corners on weight savings, optical quality, etc. is too expensive, it would be around $4500 at the cheapest, and $7000 at the most expensive. Simple fact of the matter is, you can pick up a used Canon EF 300mm f/2.8 and a 2x teleconverter for LESS than $4500, and you have yourself a 600mm f/5.6 lens that offers superb optical quality (the old EF 300mm f/2.8 was once called the sharpest lens in the world). If you want even better quality than that, you can pick up the new Canon EF 300mm f/2.8 L II for $6800, and have the best 600mm f/5.6 IQ your going to get from a lens at any price under $12000.

There simply isn't a place for a 600mm f/5.6 prime, not one that lives up to the expectations customers have for "prime" lenses. The option, with teleconverters, already exists, and even used, it tends to be well above the price point most consumers who are looking for a "cheap" 600mm lens option are willing to buy at.

A 600mm f/5.6 prime has to have good IQ. It doesn't necessarily need to be as good as the 600/4, but it has to be better than the alternatives. For such a large objective element, that is no easy task...

We are definitely in agreement...

For a 600 F5.6 prime to sell, it has to be better than the alternatives.....

At twice the price, it has to be significantly better than the Tamron... But I doubt they can hit that combination of quality and price... As mentioned above, nobody thought they could hit the quality/price on the 150-600 and they proved us wrong...I am more than willing to be proved wrong again, but I'll believe it when I see it.

Shot this with the Tamron today at 600mm. Pixel peeping on an obsolete crop body To significantly beat this at a reasonable price will certainly be a challenge.

A 600mm f/5.6 prime has to have good IQ. It doesn't necessarily need to be as good as the 600/4, but it has to be better than the alternatives. For such a large objective element, that is no easy task...

We are definitely in agreement...

For a 600 F5.6 prime to sell, it has to be better than the alternatives.....

At twice the price, it has to be significantly better than the Tamron... But I doubt they can hit that combination of quality and price... As mentioned above, nobody thought they could hit the quality/price on the 150-600 and they proved us wrong...I am more than willing to be proved wrong again, but I'll believe it when I see it.

Shot this with the Tamron today at 600mm. Pixel peeping on an obsolete crop body To significantly beat this at a reasonable price will certainly be a challenge.

Thanks for sharing Don Haines

How is the AF speed @ 600mm?

The autofocus speed seems a bit slow, but to be fair about it, I am using a 60D and every EF lens I own focuses faster on my friends 5D2 than my 60D...

A 600mm f/5.6 prime has to have good IQ. It doesn't necessarily need to be as good as the 600/4, but it has to be better than the alternatives. For such a large objective element, that is no easy task...

We are definitely in agreement...

For a 600 F5.6 prime to sell, it has to be better than the alternatives.....

At twice the price, it has to be significantly better than the Tamron... But I doubt they can hit that combination of quality and price... As mentioned above, nobody thought they could hit the quality/price on the 150-600 and they proved us wrong...I am more than willing to be proved wrong again, but I'll believe it when I see it.

Shot this with the Tamron today at 600mm. Pixel peeping on an obsolete crop body To significantly beat this at a reasonable price will certainly be a challenge.

Thanks for sharing Don Haines

How is the AF speed @ 600mm?

The autofocus speed seems a bit slow, but to be fair about it, I am using a 60D and every EF lens I own focuses faster on my friends 5D2 than my 60D...

Thanks Don,It's a $1000ish lens(@ fraction when compared to Canon 600mm II). If IQ and AF speed is good enough for everyday shooter, I think this might be a winner for many(including myself)

I just ordered the Canon 1.4TC III. Can't wait to it on my Canon 400mm f2.8 IS II.

As I said before: It's a matter of tolerances. Officina telescopes produce STUNNING quality, RAZOR sharp stars corner to corner. Because they enforce much tighter tolerances on every aspect of the scope...even down to the turbulence of the air inside the OTA in the spaces between the elements.

You get what you pay for. A $1300 APO refractor isn't going to have a flat field, it isn't going to be aberration free, it is going to suffer from thermal gradient issues and internal air turbulence problems, etc. (BTW, all of these things REALLY matter when it comes to astrophotography, they matter when it comes to the study of cosmic objects (particularly turbulence, it messes with Poisson spot shape), but they don't really matter for visual observing. You could easily get away with a $1300 APO for basic visual observation...it probably wouldn't cut it for anyone who's say looking for double or triple stars by analyzing Dawes diffraction spot shape, and it definitely wouldn't cut it for astrophotography.

canon rumors FORUM

I would be happy to give up 1/3 EV to have a 600mm prime that costs in the same range of the zoom. Or a 550mm f/5.6. There can be variations on the theme. Hell, a razor sharp 500mm f/5.6 would be interesting already.

Thanks to Tamron for proving that it's possible to manufacture such lenses at decent prices. However, for primes I would look in the Sigma direction. Some time ago they stated to be after the big whites. In fact their current 500/4.5 is not a bad lens. Their Sport category looks very barren... I wouldn't be surprised if they started populating it.

The biggest problem are the people. Most users willing to spend such amounts of money would not do so on a 3rd party lens. God, every time a hair is out of place on a Sigma lens, the litany of poor QC starts over and over again.